Effect of thoracic epidural anaesthesia on colonic blood flow.

BACKGROUND The effect of thoracic epidural block on splanchnic blood flow is unclear. It remains to be resolved if sympathetic block, increases or decreases regional splanchnic blood flow and whether regional splanchnic flow becomes dependent on cardiac output or perfusion pressure. A clear understanding of the regional haemodynamic consequences of an epidural block may modify practice with respect to epidural anaesthesia. METHODS Fifteen patients, who underwent anterior resection for rectal cancer, had invasive intraoperative monitoring of arterial pressure, central venous pressure, cardiac output, inferior mesenteric artery flow (Doppler flow probe), and colonic serosal red cell flux (laser Doppler probe), while an epidural block was established with local anaesthetic. In three consecutive time periods, arterial pressure was first allowed to fall (to a mean arterial pressure of 60 mm Hg), then treated with colloid fluid resuscitation and finally by vasopressors until the pre-epidural arterial pressure had been restored. RESULTS On induction of epidural block, there was a reduction in mean colonic serosal red cell flux to 65% and inferior mesenteric artery flow to 80% (mean) of pre-epidural levels. There was a strong association between mean arterial pressure and both measured inferior mesenteric artery blood flow (P < 0.004) and colonic serosal red cell flux (P < 0.0001). Changes in cardiac output were poorly associated with either inferior mesenteric artery blood flow (P = 0.638) or colonic serosal red cell flux (P = 0.265). Inferior mesenteric artery blood flow and colonic serosal red cell flux were restored to pre-epidural levels after arterial pressure had been improved with a vasopressor. CONCLUSION Once intraoperative epidural block has been established, colonic serosal red cell flux and inferior mesenteric artery flow are more closely associated with changes in mean arterial pressure than changes in cardiac output. The measured reduction in colonic flow does not respond to an increase in cardiac output with fluid resuscitation, but requires the use of a vasopressor to increase arterial pressure, before colonic blood flow is improved.

[1]  P. Wouters,et al.  Oesophageal Doppler monitoring overestimates cardiac output during lumbar epidural anaesthesia. , 2001, British journal of anaesthesia.

[2]  R. Leach,et al.  Effect of epidural blockade on indicators of splanchnic perfusion and gut function in critically ill patients with peritonitis: a randomised comparison of epidural bupivacaine with systemic morphine , 2000, Intensive Care Medicine.

[3]  D. Leaper,et al.  A comparison of opiate‐ and epidural‐induced alterations in splanchnic blood flow using intra‐operative gastric tonometry , 2000, Anaesthesia.

[4]  N. Rolf,et al.  Limited upper thoracic epidural block and splanchnic perfusion in dogs. , 1999, Anesthesia and analgesia.

[5]  S. Greenfield,et al.  Epidural anaesthesia and analgesia: better outcome after major surgery? , 1999 .

[6]  E. Ruokonen,et al.  Epidural analgesia with bupivacaine does not improve splanchnic tissue perfusion after aortic reconstruction surgery. , 1998, British journal of anaesthesia.

[7]  C. Sala,et al.  Effect of epidural anesthesia on colorectal anastomosis , 1997, Diseases of the colon and rectum.

[8]  H. Kehlet,et al.  Orthostatic Hypotension During Postoperative Continuous Thoracic Epidural Bupivacaine-Morphine in Patients Undergoing Abdominal Surgery , 1996, Anesthesia and analgesia.

[9]  Z. Bosnjak,et al.  Region of Epidural Blockade Determines Sympathetic and Mesenteric Capacitance Effects in Rabbits , 1995, Anesthesiology.

[10]  K. Espersen,et al.  Comparison of cardiac output measurement techniques: thermodilution, Doppler, GO2‐rebreathing and the direct Fick method , 1995, Acta anaesthesiologica Scandinavica.

[11]  B. Parker,et al.  Postoperative Epidural Bupivacaine‐Morphine Therapy Experience with 4,227 Surgical Cancer Patients , 1994, Anesthesiology.

[12]  Z. Bosnjak,et al.  Effects of Epidural and Systemic Lidocaine on Sympathetic Activity and Mesenteric Circulation in Rabbits , 1993, Anesthesiology.

[13]  D. Arand,et al.  Sympathetic blockade by thoracic epidural anaesthesia suppresses renin release in response to hypotension, but activates the vasopressin system. , 1992, European journal of anaesthesiology.

[14]  L. Norgren,et al.  Intestinal Hemodynamics During Laparotomy: Effects of Thoracic Epidural Anesthesia and Dopamine in Humans , 1990, Anesthesia and analgesia.

[15]  R. Baird,et al.  Operative assessment of femorodistal bypass grafts using a new Doppler flowmeter , 1989, The British journal of surgery.

[16]  E. Bennett,et al.  Continuous hemodynamic monitoring by esophageal Doppler. , 1989, Critical care medicine.

[17]  H. Ahn,et al.  Effect of epidural anaesthesia on intestinal blood flow , 1988, The British journal of surgery.

[18]  K. Kvernebo,et al.  Evaluation of endoscopic laser Doppler flowmetry for measurement of human gastric blood flow. Methodologic aspects. , 1988, Scandinavian journal of gastroenterology.

[19]  O. Lundgren,et al.  Measurement of colonic blood flow with laser Doppler flowmetry. , 1986, Scandinavian journal of gastroenterology.

[20]  K. Kvernebo,et al.  Human gastric blood circulation evaluated by endoscopic laser Doppler flowmetry. , 1986, Scandinavian journal of gastroenterology.

[21]  J. Arndt,et al.  Peridural anesthesia and the distribution of blood in supine humans. , 1985 .

[22]  J. Arndt,et al.  Peridural Anesthesia and the Distribution of Blood in Supine Humans , 1985, Anesthesiology.

[23]  A. P. Shepherd,et al.  Continuous measurement of intestinal mucosal blood flow by laser-Doppler velocimetry. , 1982, The American journal of physiology.